Hobbies

How to Etch Brass or Copper

Chemically etching a design into Brass or Copper delivers sharp professional results even on the first attempt. The skills needed to etch brass are pretty basic, so if you want to create a great looking design that will quite literally last for centuries, etching metal is the way to do it.

Acid etched Brass plate

The key elements are Firstly a piece of metal on which you want to place a design. For this tutorial I am using a 0.9mm thick piece of brass, cut to approximately three inches by four inches.

The second element is a chemical to etch brass with .

Ferric Chloride is the popular metal etch because it is strong enough to get the job done in a sensible timescale but not so strong that you are likely to put yourself in hospital.

Ferric Chloride
Ferric Chloride etching solution.

The third part of the process is to create a design and stop parts of the metal that you don’t want etched to remain unaffected by the Ferric Chloride.

Creating a design

There are a number of ways to achieve this. The simplest method is to draw your design directly onto a piece of brass or copper or even silver, with a pen that resists the etching solution. Surprisingly a Sharpie black marker does the job nicely. However most of us aren’t exactly Picasso, so you may want to work up your design on a computer and then print it out. Since you want a two colour black and white image, you should consider using a vector illustration software package such as Inkscape, but any paint program will do the job.

Remember to reverse your design so that lettering appears in reverse on the screen. that way, when you transfer the image it will end up the right way round. One key point to remember is that lines that are less than 2 pixels wide may be too narrow to get properly etched. Having said that, a design with lots of fine lines can often look spectacular. I recommend experimenting to see what works and what doesn’t. If it looks good printed full size on a piece of paper it should look good when it eventuallying appears as a brass etching.

Transferring a design onto Metal.

You can buy special etching inks and special paper, but I found great results came from using a laser jet printer on shiny inkjet photo paper. The laser jet ink is actually a plastic (great for stopping the Ferric Chloride) and the inkjet paper doesn’t absorb it, so it will transfer from the paper to the metal with relative ease. To transfer the ink from the paper, we use heat from a household iron.

Lay down a few sheets of protective newspaper on your ironing board and put your metal plate on top. Lay the laserjet image face down onto the metal. Add a couple more newspaper sheets to protect the surface of your your iron and start pressing. About a minute under a constantly moving hot iron is enough. Once the minute is up, take the iron away and leave the object alone to cool. Let it get properly cold before removing the newspaper or moving anything.

Now comes the fun bit. Even if you peel away the laserjet paper now, There will be a paper residue on the Brass or Copper. Simply soak the metal and paper in water for an hour or so to soften the paper and then very gently rub away the paper with your finger. With a simple design this could take moments, but with a complex design it could take you anything up to an hour. I find this part really enjoyable and I like to take my time about it.

Now you have your resist on the metal. However there may be a few spots where you rubbed to hard, so go over the whole thing with a magnifying glass to make sure you have everything as perfect as you want it to be.

Use packing tape to quickly create a resist covering the entire back and sides of the metal plate.

Ferric Chloride Etching

Now you need to start etching. A small disposable plastic tray is perfect to act as a bath where the etching will occur. If the tray is a bit too big, don’t worry that you will be wasting ferric Chloride. The liquid is reusable time and again, so you don’t need to worry on that score.

Plastic tray for etching

Use more tape to suspend your metal sheet in the bath face down so it is not touching the bottom.

Brass sheet suspended face down in etching bath.

Now pour in enough Ferric Chloride to cover the metal sheet. Gently agitate to get rid of any bubbles. By etching face down, the etched material can fall away to the bottom of the bath so there is less chance of leaving you with an uneven result.

Leave it alone for fifty minutes as the unstoppered brass is etched away. Rinse and then scrub away the stopping ink as it has done its job now. Once clean, polish your brass.

An optional final step when you etch brass is to fill in the etched areas with dark oil paint. This can really make the design stand out.

Safely disposing of Ferric Chloride

Once used, Ferric Chloride solution must not be put down the drain because of the suspension of copper left in it. As I mentioned earlier, the liquid can be reuse many times so pour it back in the bottle or into a suitably marked non-metallic container.

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